I think a dirty bomb (Radiation threat) or a limited terrorist attack on a major city with a "suitcase nuke". If you are not in the immediate area of a nuke burst then you will be concerned with the downwind fallout. I would find out what the prevailing winds are in your area and what they are for any area attacked. Read on how to protect against these types of radiation, there is a lot of info out there, see attachement:

Alpha

Beta

Gamma

I think the biggest threat to those not in an area of attack is not being stocked up on food and water and other necessary supplies.

How well does Potassium Iodide work? Is it the wonderdrug that some say it is against radiation.

From what I have read the way it works is, your body keeps a curtain amount of iodine from your diet. Some forms of iodine are radioactive so you taking potassium iodide fills your bodies iodide quota so when the radioactive stuff passes through your body harvest.

Excellent - A person that knows a thing or 2 about NBC. I think a lot of folks just plan on grabbing a surplus mask of lord knows what origin and putting it on their face if need be. Anyone that has had formal training in this area knows better then that. Thank for the post and good luck.

Its an honor to have you as a member of this community. Thank you for the offer.

One of the questions that I have, what does the government consider the most serious biological threat to the USA is? Is it man made or natural?

Man made can kill more then a natrual disaster I dont know which one they are more affraid of though.. Biological and chemical warfare are nasty.. and can kills 100s of millions of people and leave the infrstructer in tact... I know place that have virses like small poxs and if that got out it would be nasty.. Plus during the cold war russia even admited to makeing the virse work to use as a weapon.. Something that spreads between people easly and is deadly is hard to stop because once panic starts it spreads fast..

Yes, but they have a shelve life and you must know how to wear them properly. I do not own a mask or a suit at this time, but plan to buy a few masks. Make sure you know how to don (put on) and clear them (blow contaminated air from mask) properly.